IS there ground transportation to Mclean, VA from the station? If so, what is available?

There are several taxis available outside the station

Buses, Uber and Metro (DC's Subway System) to McLean, VA. Silver Line goes to McLean. Double check with Google Maps App to route out your trip.

Metro. Google maps

Silver Line Metro from Union Station

You can check Google Maps route to McLean. Some buses are there